find n features with a start > than `position` f: a IntervalTree::Interval object (or anything with an `end` attribute) n: the number of features to return max_dist: the maximum distance to look before giving up.

find n features with a end < than position f: a IntervalTree::Interval object (or anything with a `start` attribute) n: the number of features to return max_dist: the maximum distance to look before giving up.

Basic feature, with required integer start and end properties. Also accepts optional strand as +1 or -1 (used for up/downstream queries), a name, and any arbitrary data is sent in on the info keyword argument